Its been a while, I use to fly a lot in that region. I use to fly a Cessna 210 turbo most of the time. Icing is a problem, along with not being able to get high enough for some of the routes. I would not fly with out supplemental Oxygen. I had a provideded tank, it dried me out all the time. Its a must for night. You can do with out pressurization, I would like at least a turbo charged engine. Non- turbo charging is doable. Just plan on flying at less than Gross Weight. You just look at the performance charts for your aircraft and plan accordingly.